Two stage reforming with noble metal catalyst



Sept. 22, 1959 R. D. BAUER ETAL Two STAGE REFORMTNG WITH NOBLE METAL cATALYsT Filed March 2, 1956 INVENTRs R D BA U E R NW MITCHELL BYM mEOFPOm vilain liti Al BLVNOIiDVBd-ld Dumm nitetl States Patent "fee TWO STAGE REFORMING WITH NOBLE METAL CATALYST Robert D. Bauer and Norris W.l Mitchell, Bartlesville, Okla., assignors to Phillips Petroleum Company, a corporation of Delaware Application March, 2, 1956, Serial No. 569,202 l2 Claims. (Cl. 20K-65) This invention relates to the production of high quality motor fuel. In one aspect it relates to a method for the production of high octane number motor fuels. In another aspect it relates to a method for the production of high octane number motor fuels in increased yield o'ver conventional methods of producing such fuels.

' An object of this invention is to provide a method for producing high quality motor fuels.

Another object of this invention is to provide a method for producing high octane number motor fuels.

Still another object of this invention is to provide a method for the production of high octane number motor fuels from low octane number feed stocks.

Yet another object of this invention is to provide such a method for the production of high octane fuels which is simple and easy to operate.

Still other objects and advantages of this. invention will be realized upon reading the following description, which, taken with the attached drawing, form a part of this specification.

The drawing illustrates, in diagrammatic form, one arrangement of apparatus parts for carrying out the process of this invention.

This invention provides a distinct advantage over prior art methods for improving octane numbers of hydrocarbon fuels by modifying conventional processes. Modifyi'ng a conventional process to our improved process requires only a minimum of apparatus change.

One prior art method of improving octane numbers of motor fuel stocks involves fractionation of a low octane value feed stock to produce a low boiling fraction and a high boiling fraction, catalytically converting the high boiling fraction in the presence of a platinum containing catalyst and then after removing, for example, butane and lighter, from the conversion efliuent, combining the remainder of the eiiluent with the originally separated low boiling fraction and converting this cornbined material in a second conversion step in the presence of a platinum containing catalyst. Both of these conversions are in the presence of free hydrogen.

We have found that not only is it not necessary but in fact it is disadvantageous to convert in a second conversion zone the entire liquid product, free from butane and lower boiling materials, of the lirst conversion zone because a substantial proportion of the liquid eflluent of the first conversion zone possesses a very high octane number and obviously such high octane number material need not be retreated. Retreating such high octane material ordinarily yields` little to no` further octane increase, but with a volume loss, and even may produce a product of lowered octane number with a volume loss. Accordingly, we fractionate the liquid product of the rst conversion zone and from this fractionation we remove the high boiling fraction as a high octane product of the process and we then combine the low boiling fraction from the effluent of the first conversion with the low boiling fraction from the original feed stock and convert this combined material in the presence of a sec- 2,905,621' Patented Sept. 22, 1952 ond platinum containing catalyst. Both conversion steps of course are in the presence of free hydrogen. Based on 19,200 barrels of original feed stock we are able to produce 16,500 barrels of 96 octane number Platformate with 3 cc. TEL per gallon by the Research Method in contrast to the production of only 16,200 barrels of 96 octane number Platformate with 3 cc. TEL per gallon by the Research Method, by the above mentioned prior art method. At first thought it might be considered. that 16,500 barrels in contrast to 16,200 barrels is not a very great increase in yield, but when one considers that this material with 3 cc. TEL per gallon possesses anv octane number of 96 (by the Research Method) the value. of 300 barrels per day of such a high octane number gasoline stock is appreciable. v

Specifically we have discovered a method for upgrading` the octane rating of a low octane rating gasoline comprising separating said gasoline into a first low boiling fraction and a first high boiling fraction, contacting the first high boiling fraction in the vapor phase and under Platforming conditions with a first platinum containing catalyst, from the effluent of this first vapor phase contacting operation separating a second low boiling fraction and a second high boiling fraction, combining said first low boiling fraction with said second low boil.- ing fraction,l contacting this combined material in the vapor phase under Platforming conditions with a second platinum containing catalyst, combining the eflluent of this second vapor phase contacting operation with the eflluent of the first vapor phase contacting operatiom'and removing said second high boiling fraction as an up'-` graded octane number gasoline product.

Furthermore we upgrade low Octane value gasoline stocks by contacting in the vapor phase and under first Platforming conditions a low octane value gasoline stock with a first platinum containing catalyst, withdrawing eluent from this first operation, fractionating said eiliu.- ent into a low-boiling fraction and a high-boiling frac` tion, contacting said low-boiling` fraction in the vapor phase and under second Platforming conditions with a second platinum containing catalyst, combining effluent from this second operation with the efuent from the first operation and withdrawing said high boiling fraction as the upgraded octane value product of the process. The platinum containing catalyst which we use in the conversion steps of our invention is made by any suitable process. A specific method for preparing such a catalyst is disclosed in U.S. Patent 2,479,109. This disclosed method, briefly stated, involves precipitation of a salt of aluminum, such as aluminum chloride, with for example,

is then introduced into the mixture at room temperature. Alternatively, hydrogen is added to the aqueous chloroplatinic acid and then the mixture slurried with the halide containing aluminum hydroxide. The hydrogen sulfide apparently reacts with the chloroplatinic acid to form one or more complex chemical compounds which are easily retained by the aluminum hydroxide upon 'filtrationv of same. The platinuml containing mixture is dried` at av temperature of about 200 to 400 F. for a period of 4 The catalyst can be formed into pills ofy uniform size or into other shapes as desired after which.`v`l

to 24 hours.

itis calcined at a temperature about 800217200912. for

about 2 to 8 hours or more. After this. calcining treat-f; Y ment the catalyst is ready for use.

After such a catalyst has been used and deposition of After the aluminum hydroxide and,` halide are thoroughly mixed, platinum in the form 'of'- aqueous chloroplatinic acid is added. Hydrogen sulfider carbonaceous matter thereon has diminished its catalytic activity, the catalyst is regenerated by heating to a tern-I perature not exceeding about 1200" F. in the presence of a free-oxygen containing gas, such as air.

j VThe catalyst prepared as above outlined promotes aromatization, cyclization, isomerization and other reactions characteristic of hydrocarbons.

The general rule found applicable in the practice of our invention is that the low boiling material is susceptible to octane number improvement by Platforming without undue volume loss whereas high boiling Platformate material is not susceptible to octane number improvement by further Platforming without undue volume loss. The volume loss by Platforming a high boiling'Platformate material is usually suiciently great as to make uneconomicalfurther treatment of the higher boiling; materials.

, Material or feed stock susceptible of treatment according 'to our herein disclosed method includes straight run and/orcracked naphthas.

Bythe term low boiling fraction as used throughout this `Specification and claims is meant that relatively low boiling Platformate material which is susceptible to further octane number improvement by a subsequent Platforming operation without undue volume loss whereas the term high boiling fraction as used throughout this specication and claims includes Platformate material of boiling range higher than the boiling range of said low boiling fraction and is used in blending spark ignition engine fuels for automotive and aviation use andy is not susceptible to further octane number improvement by Platforming without undue volume loss.

, By the term cut point is meant the temperature intermediate the low boiling fraction and the high boiling fraction and is actually the temperature at which the cut is made to produce the low boiling fraction and the high boiling fraction. ,The cut point of the Platformate as in Platformate splitter or fractionator 14 depends upon several factors; ciirst, the source of the crude oil providing the straight run and/or cracked naphtha feed to the prefractionator 2; second, the specific `operating conditions maintained -in the Platforming reactors 8 and 23; third, the desired octane number of the inal product, and on such other conditions as hydrogen recycle, degree of stabilization or fractionation carried out in columns 2 and 13, etc. 'Ivfhose skilled in the art understand the adjusting and regulation of the operating conditions in order to produce a final product having the desired octane value;

i As illustrative of the operation of our process, a feed stock, such as a naphthenic gasoline, from a source, not shown, is passed through pipe 1 into a fractional distillation zone 2 in which it is fractionated into `a low boiling overhead fraction, a high boiling fraction, and a residue The high boiling fraction is passed from the fractionation zone 2-through a pipe 4 is vaporized in furnace 7, and is then passed into a reactor vessel 8 containing'a quantity of theabove mentioned platinum containing catalyst.' -Free hydrogen, as subsequently produced, is introduced from a pipe 6 into the stream of high boiling gasoline prior to its entry into furnace 7. This furnace 7 is operated in such a manner as to vaporize without coking the gasoline so that it can be introducedina vapor phase into the reactor 8. This reactor 8 is maintained at a temperature of from about 800 to 975 F. at a pressure of from 300-700 p.s.i.g. The rate of introduction of the feed stream into the reactor is such as to provide a' ow'rate of from 2 to 8 liquid volumes of feed per volume of catalyst per hour. The rate of introduction of hydrogen into this feed stream is from about 2:1 to 10:1

mols of free hydrogen per mol of high boiling gasoline feed.

The eiuent from the reactor 8, partially condensed inl ate splitter column 14.

. 4 ser 9 are removed in pipe 6 and are compressed by a compressor 26 prior to introduction into the feed stream in pipe 4. This hydrogen containing gas is rich in hydrogen and is the free hydrogen as subsequently produced, mentioned above. Excess of hydrogen not required in reactor 8 is removed from the system through a pipe 27 for such disposal as desired.

The liquid phase from separator 10 is removed therefrom through a pipe 11 and is passed into a stabilizer 13 from which butane and lower boiling materials are removed through a pipe 28. The stabilizer bottoms (or Plat-formate) is passed through a pipe 34 into a Platform- In this splitter column the Platformate is fractionally distilled and the low boiling fraction is removed through a pipe 15 and the kettle material is removed through a pipe 33 as a portion of the high octane Platformate product of the process. The low boiling fraction passing through pipe 15 is combined with the low boiling fraction of the original feed stock from pipe 5 and this combined material passes through a pipe 32 into la selective charge splitter column 16. The use of this splitter column 16 is not essential to our process, but if desired it can be used to distill a low boiling fraction or cut which is removed through a pipe 17, an intermediate boiling fraction which is removed through a pipe 18 and a high boiling fraction which is removed through a pipe 19. vAccording to local requirements, any one or two of these three cuts or fractions from splitter column 16 can be removed as additional products of the process While the third one, which can be any one of the three cuts, can be passed on through pipe 29, 30, or 31, as the case may be, and pipe 20 into the second stage of our operation.

However, under some conditons it may not be desired to remove any fraction of the combined stream owing through pipe 32 as product, and in this case a valve in pipe 32 (feed line to splitter 16) is closed and a valve in pipe 36 is opened and the combined feed material passes directly through pipe 36 into pipe 20 for our second stage of operation.

The material passing through pipe 20 is vaporized in a heater 22 and in the vapor form it is passed into a reactor vessel 23 which contains a quantity of, for example, the same platinum containing catalyst as is employed in reactor 8. Reactor 23 is maintained at a temperature of` approximately 850 and 1000 F. under a pressure of about .250 to 600 p.s.i.g. or about 250 to 600 p.s.i.g. The volume of the catalyst in reactorvessel 23 is such that the feed stock in the vapor form is passed through the reactor at a feed rate of about 2 to 8 liquid volumes of feed per volume of catalyst per hour.

Effluent from reactor vessel 23 is passed through a line 37, is at least partially condensed in condenser 24, and liquid is separated from gas in a separator tank 25. The liquid separated in tank 25 is passed by way of a pipe 12 and is combined with the liquid from separator tank 1I) flowing in pipe 11 and it is this combined stream which is passed into stabilizer 13. A portion of the liquid from separator 25 is included in the high octaneA number high boiling portion separated in splitter 14 and' this hydrogen-rich gas is passed through a pipe 21 and iscompressed by a compressor 38 and is introduced into the charge stock owing through pipe 20 prior to its entry'into furnace 22. The rate of addition of this hydrogen-rich gas tothefeed in pipe 20 is such as to maintain a mol ratio of hydrogen to feed between the approximate limits of 2:1 to 10:1 on a mol basis preferably from 4:1 to 9:1. AnyV excess OfhydrOgen-rich vgas over that requiredY to maintain this recycle ratio is removed from pipe 21 through a pipe35 for such disposal as desired.

When the system is treating a naphthenic base gasoline;

we operate splitter 14 so as to take approximately 40- per'- cent of the material charged to this splitter overhead through pipe 15 so that it is only about 40 percent of the stabilized effluent from reactor 8 which is reprocessed in the subsequent reactor 23. In this manner the high boi-ling fraction separated in splitter 14 is not retreated, as is done in the aforementioned prior art, with possible deterioration of its normally high octane rating. In the example given herebelow this high boilingV fraction withdrawn through pipe 33 had an octane number" of 96. While subsequent treatment might under some conditions not adversely affect the octane rating of this material subsequent treatment does not further improve its octane number and such retreating would merely increase the load on furnace 22 and reactor 23.

rIn the following tabulation are given data on a run inwhich a Platformate stock was fractionally distilled toproduce a 40% by volume overhead product and a 60% kettle product byv volume less a volume loss of about 0.64%. The octane number values are illustrative ofthe diie'rence in properties of a lowboiling fraction and a high boiling fraction of a Platformate stock:-

I Vol. loss on distillation 0.64%.

As an example of the operation ofr our process, a naphthenic type gasoline was fractionated in a' fractionator corresponding to fractionator 2 with the high boiling fraction being catalytically treated in the presence of a platinum containing catalyst and the liquid eluent therefrom fractionated in a splitter corresponding to splitter I4. Approximately 40 percent ofthe charge to splitter 14 was removed as overhead product and combined with the low boiling fraction ofthe original `gasoline and this combined vmaterial was vaporized and treated in the presence of thesecond platinum containing catalystyin a vessel corresponding .to reactor 23. Condensate liquid separated from the effluent. of this latter reactor was combined'with the liquid separated from the eiuent of the rst stage reactor. In the following tabulation are given the ilow rate in terms of barrels per day. and the octane number ofthe streams-of product in various stages of an operation illustrated in the drawing.

Prior art the 'heading Prior art in the tabulation are given the ow rate in terms of barrels'per lday and octane of the oriesptmding` streams of the'prior art process as herelinabove described. It should be noted that the nal product of our process as removed through pipeV 33Y is 16,500- barrels based on a feed volume of 19,200 barrels (pipes 5 and 4) and having an octane number of 96 (+3 cc. TEL) in contrast to the prior art tinal product of 16,200 barrels of 96 octane gasoline (+3 cc. TEL) based on the same volume of feed stock. Thus, our process produces 300 barrels of 96 octane gasoline (+3 cc. TEL) more per 19,200 barrels of charge stock than does the prior art.

In one particular case when a naphthenic type' of gasoline was treated according to our process, fractionation cuts numbers 1, 2, and 3 withdrawn from splitter 16 through pipes 17, 1S, and 19, respectively, consisted largely of C5, C6, and C7 hydrocarbons, respectively.

In 4the prefracti'onator 2, it is ordinarily desired to separate out and to withdraw from the system such high boiling material as would tend to coke up the Platforming catalyst in the reactor 8. The fraction removed overhead from the vessel is in general mainly the low boiling material which would not be appreciably converted under the relatively mild conditions maintained in the Platforming reactor 8 for converting the higher boiling portion of the feed taken oit tower 2 via pipe 4. The material taken overhead from prefractionator 2 acts largely as a diluent of the more easily converted higher boiling material in reactor 8 thereby reducing the Platforming capacity of this reactor. However, this overhead material is suitable as Platforming charge stock to reactor 23 which is maintained under suitable conditions to convert this low boiling less easily converted stock to a high octane value stock.

In the example given herein, approximately 40% of the feed to Platformate splitter 14 was taken overhead as the low boiling fraction for subsequent treatment in reactor 23. As mentioned hereinbefore the cut made in thel splitter is largely dependent on the desired results, and accordingly more than 40% by Volume or less than 40% by rvolume can be taken overhead for retreatment dependent upon the octane value of the portion not taken overhead, that is the bottoms withdrawn via pipe 33. The volume percentage taken overhead rarely exceeds 70%.

It will be obvious to those skilled in the art that operational details such as reactor temperatures, pressures, stock How rates, hydrogen recycle rates, composition of cuts l, 2, and 3 from splitter 16, and many other details will need to be changed in View of the particular feed stock being treated and the ultimate results desired. Such changes in operational details will be Well understood by those skilled in the art.

Such auxiliary apparatus as valves, temperature and pressure indicating, recording and control apparatus andA the like are not shown on the drawing or described in the specification for purposes of brevity. The need for such auxiliary equipment, its installation and use are well understood by those skilled in such art.

While certain embodiments of the invention have been described for illustrative, purposes, the invention isobviously not limited thereto.

I claim:

1. A method for upgrading the octane rating of low octane rating gasoline stocks comprising the steps of contacting in the vapor phase and under iirst Platforming conditions of about 800 to 975 F. and about.300 to 700 p.s.i.g. a low octane value gasoline stock with a rst platinum containing catalyst, withdrawing effluent from this first operation, fractionating said efuent into a low boiling fraction which is susceptible torfurther` octanenumber improvement; and a high octane number high boiling fraction which is not susceptible to further octane number improvement without undue voltune loss, contacting said low boiling fraction in the vapor phase and under second Platformingv conditionsv ofabout .85010 1000 F. and about 300 to 600 p.s.i.g. with a vsecond asomarv platinum containing catalyst, combining eluent from this second operation with the efliuent from the first operation prior to the fractionation step and withdrawing said high boiling fraction as the upgraded octane value product of the process.

2. A method for upgrading the octane rating of low octane rating gasoline stocks comprising the steps of contacting in the vapor phase and under first Platforming conditions of about 800 to 975 F. and about 300 to 700 p.s.i.g. a first low octane value gasoline stock with a rst platinum containing catalyst, withdrawing euent from this rst operation, fractionating said efliuent into a low boiling fraction which is susceptible to further octane number improvement; and a high octane number high boiling fraction which is not susceptible to further octane number improvement without undue volume loss, to this low boiling fraction adding a low boiling low octane value gasoline stock, contacting this latter combined material in the vapor phase and under second Platforming conditions of about 850 to l000 F. and about 300 to 600 p.s.i.g. with a second platinum containing catalyst, combining effluent from this second contacting operation with the effluent from the rst operation prior to the fractionation step, and withdrawing said high boiling fraction as the upgraded octane rating gasoline stock. v 3. A method for upgrading the octane rating of a low octane rating gasoline, comprising fractionally distilling said gasoline into a low boiling material which is not easily converted in a subsequent step and a high boiling material more easily converted in said subsequent step, contacting said high boiling material in the vapor phase at a vtemperature within about 800 to 975 F. under superatmospheric pressure of about 300 to 700 p.s.i.g. with a first platinum containing catalyst as said subsequent step at a flow rate of 2 to 8 liquid volumes of said high boiling material per volume of catalyst per hour, from the efuent of this iirst vapor phase contacting operation separating a first vapor phase from a iirst liquid phase, from this first liquid phase separating a low boiling fraction which is susceptible to further octane number improvement; and a high boiling fraction which is not susceptible to further octane number improvement without undue volume loss, combining the aforesaid low boiling material with said low boiling fraction, contacting this combined material in the vapor phase at a temperature within about 850 to 1000 F. under superatmospheric pressure of about 250 to 600 p.s.i.g. with a second platinum containing catalyst at a flow rate of 2 to 8 liquid volumes of said combined material, the temperature of the contacting with said second catalyst being at a higher temperature than the temperature of contacting with said iirst catalyst, the pressure maintained in the second catalytic step being; lower than the pressure maintained in the first catalytic step, from the euent of this second vapor phase contacting operation separating a second vapor phase from a second liquid lphase, combining this second liquid phase with the aforesaid first liquid phase, and withdrawing said high boiling fraction as an upgraded octane number gasoline product.

4. In .the method of claim 3 cycling at least a portion of said first vaporphase into the rst vapor phase contacting operation as a hydrogen recycle and at least a portion of said second vapor phase into the second vapor phase contacting as a second hydrogen recycle the hydrogen recycled being from about 2 to 10 mols hydrogen per rnol of feed to each vapor phase contacting.

5. A method for upgrading the octane rating of a lowoctane rating gasoline, comprising fractionally distilling said gasoline into a low boiling material which is not easily converted in a subsequent step and a high boiling material more easily converted in said subsequent step, ,contacting said high boiling material in the vapor phase at'pa temperature Within about 800 to 975 F.

under superatmosphere pressure of about 300 to 700 p.s.i.g. with a iirst platinum containing catalyst as said subsequent step, from the effluent of this first vapor phase contacting operation separating a lirst vapor phase from a first liquid phase, from this first liquid phase separating a low boiling fraction which is susceptible to further octane number improvement; and a high boiling fraction which is not susceptible to further octane number improvement without undue volume loss, combining said low boiling material with said low kboiling fraction, fractionating this combined material into a second low boiling fraction, a rst intermediate boiling fraction and a second intermediate boiling fraction, contacting atv least one of said second low -boiling fraction, said first intermediate boiling fraction and said second intermediate boiling .fraction in the vapor phase at a temperature within about 850 to 1000" F. under superatmospheric pressure of about 250 to 600 p.s.i.g. with a second platinum containing catalyst, the temperature of the contacting with said second catalyst being at a higher temperature than the temperature of contacting with said first catalyst, the pressure maintained in the second catalytic step being lower than the pressure maintained in the first catalytic step, from the eiiiuent of this second vapor phase contacting operation separating a second vapor phase from a second liquid phase, combining this second liquid phase with the aforesaid rst liquid phas'e, withdrawing said high boiling traction as an upgraded octane number gasoline product, and withdrawing the other two of said second low boiling fraction, said first intermediate boiling fraction, and said second intermediate boiling fraction as additional products.

6. A method for upgrading the octane rating of a low octane rating gasoline, comprising fractionally distilling said gasoline into a low boiling material which is not easily converted in a subsequent step and a high boiling material more easily converted in said subsequent step, contacting said high boiling material in the vapor phase at a temperature within about 800 to 975 F. under superatmospheric pressure of about 300 to 700 p.s.i.g. and in the presence of from 2 to 10 mols free hydrogen per mol of said high boiling material with a first platinum containing catalyst as said subsequent step, from the efliuent of this rst vapor phase contacting operation separating a first vapor phase from a first liquid phase, from this first liquid phase separating a low boiling fraction which is susceptible to further octane number improvement; and a high boiling fraction which is not susceptible to further octane number improvement without undue volume loss, combining said low boiling material with said low boiling fraction, fractionating this combined material into a second low boilingfraction, a

iirst intermediate boiling fraction and a second intermediate boiling fraction, contacting as charged at least one of said second low boiling fraction, said first intermediate boiling fraction and said second intermediate boiling fraction in the vapor phase at a temperature within about 850 to 1000 F. under superatmospheric pressure of about 250 to 600 p.s.i.g. and in the presence of fromV 2 to l0 mols free hydrogen per mol bf said charge with a second platinum containing catalyst, the temperature of the contacting with said second catalyst being at a higher. temperature than the temperature of contacting with said first catalyst, the pressure maintained in the second` catalytic step' being lower than the pressure maintained 1n the first catalytic step, from the eliluent of this second vaporY phase Y-contacting operation separating a secondvapor phase from a second liquid phase, combining this second liquid phase with the aforesaid rst liquid phase, withdrawing said high boiling fraction as an upgraded octane number gasoline product, and withdrawing the remaining of said second low boiling fraction, said iirst'V intermediate fraction, and said second intermediate boiling fraction as additional products.

7. A method /forupgrading the octane rating Vofalowcy octane rating gasoline, comprising fractionaffy distilfing said gasoline into a low boiling material which is not easily converted in Va subsequent step and a high boiling material more easily converted in said subsequent step, contacting said high boiling material in the vapor phase at a temperature within about 800 to 975 F. under superatmospheric pressure of vabout 300 to 700 p.s.i.g. with a first platinum containing catalyst as said subsequent step at a fiow rate of 2 to 8 liquid volumes of said high boiling material per volume of catalyst per hour, from the eflluent of this first vapor phase contacting operation separating a first vapor phase from a first liquid phase, from this first liquid phase distilling a low boiling fraction which is susceptible to further octane number improvement; and a high boiling fraction which is not susceptible to further octane vnumber improvement without undue volume loss, combining said low boiling material with said low boiling fraction, fractionating this combined material into a second low boiling fraction, a first intermediate boiling fraction and a second intermediate boiling fraction, contacting as charge at least one of said second low boiling fraction, said first ntermediate boiling fraction and said second intermediate boiling fraction in the vapor phase at a temperature within about 850 to 1000 F. under superatmospheric pressure of about 250 to 600 p.s.i.g. with a second platinum containing catalyst at a flow rate of 2 to 8 liquid volumes of said charge, the temperature of the contacting with said second catalyst being at a higher temperature than the temperature of contacting with said first catalyst, the pressure maintained in the second catalytic step being lower than the pressure maintained in the first catalytic step, from the efiiuent of this second Vapor phase contacting operation separating a second vapor phase from a second liquid phase, combining said second liquid phase with the aforesaid first liquid phase, withdrawing said high boiling fraction as an upgraded octane number gasoline product, and withdrawing the other -two of said second low boiling fraction, said first intermediate boiling fraction, and said second intermediate boiling fraction as additional products.

8. In the method of claim 6 cycling at least a portion of said first vapor phase into the first vapor phase contacting as the first mentioned 2 to 10 mols of free hydrogen and cycling at least a portion of said second vapor phase into the second vapor phase contacting as the second mentioned 2 to l0 mols of free hydrogen.

9. A method for upgrading the octane rating of a low octane rating gasoline, comprising fractionally distilling said gasoline into a low boiling material which is not easily converted in a subsequent step and a high boiling material more easily converted in said subsequent step, contacting said high boiling material in the vapor phase at a temperature within about 800 to 975 F. under superatmospheric pressure of about 300 to 7 00 p.s.i.g. with a first platinum containing catalyst as said subsequent step, from the efliuent of this first vapor phase contacting operation separating a first vapor phase from a first liquid phase, fractionating this first liquid phase into a low boiling fraction which is susceptible to further octane number improvement; and a high boiling fraction which is not susceptible to further octane number improvement without undue volume loss, combining said low boiling material with said low boiling fraction contacting this combined material in the vapor phase at a temperature within about 850 to 1000 F. under superatmospheric pressure of about 250 to 600 p.s.i.g. with a second platinum containing catalyst, the temperature of the contacting with said second catalyst being at a higher temperature than the temperature of contacting with said first catalyst, the pressure maintained in the second catalytic step being lower than the pressure maintained in the first catalytic step, from the effluent of this second vapor phase contacting operation separating a second vapor phase from a second liquid phase, combining this 10 second liquid phase with the aforesaid first liquid phase and withdrawing said second high boiling fraction as an upgraded octane number gasoline products.

1'0. A method for upgrading the octane rating ofv a low octane rating gasoline, comprising fractionally disv` tilling said gasoline into a low boiling material whichv is not easily converted in a subsequent step and a high boiling material more easily converted in said subsequent step, contacting said high boiling material in the vapor phase at a temperature within about 800 to 975 F. under superatmospheric pressure of about 300 tov 700 p.s.i.g. and in the presence of from 2 to 10 mols of free hydrogen per mol of said high boiling fraction with a rstplan'num containing catalyst as said subsequent step, from the efii'uent of this first vapor phase contacting operation separating a first vapor phase from a first liquid phase, from this first liquid phase fractionally dis'- tilling a low boiling fraction which is susceptible to further octane number improvement; and a high boiling fraction which is not susceptible to further octane number irnprovement without undue volume loss, combining said low boiling material with said low boiling fraction, contacting this combined material in the vapor phase at a temperature within about 850 to 1000 F. under superatrnospheric pressure of about 250 to 600 p.s.i.g. and in the presence of from 2 to 10 mols free hydrogen per mol of combined low boiling materials with a second platinum containing catalyst, the temperature of the contacting with said second catalyst being at a higher temperature than the temperature of contacting with said first catalyst, the pressure maintained in the second catalytic step being lower than the pressure maintained in the first catalytic step, from the efiiuent of this second vapor phase contacting operation separating a second vapor phase from a second liquid phase, combining this second liquid phase with the aforesaid first liquid phase, and withdrawing said second high boiling fraction as an upgraded octane number gasoline product.

ll. A method for upgrading the octane rating of a low octane rating gasoline, comprising fractionally distilling said gasoline into a low boiling material which is not easily converted in a subsequent step and a high boiling material more easily converted in said subsequent step, contacting said high boiling material in the vapor phase under Platforming conditions of about 800 to 975 F. and about 300 to 700 p.s.i.g. with a first platinum containing catalyst as said subsequent step, withdrawing contacted efiiuent from this operation, fractionating this withdrawn efiiuent into a low boiling fraction which is susceptible to further octane number improvement; and a high boiling fraction which is not susceptible to further octane number improvement without undue volume loss, combining said low boiling material with said low boiling fraction, contacting this combined material in the vapor phase under Platformng conditions of about 850 to 1000 F. and about 250 to 600 p.s.i.g. with a second platinum containing catalyst, the temperature of the contacting with said second catalyst being at a higher temperature than the temperature of contacting with said first catalyst, the pressure maintained in the second catalytic step being lower than the pressure maintained in the first catalytic step, withdrawing contacted second efiluent from this second contacting operation, combining effluent of this second vapor phase contacting operation with efiluent of said first vapor phase contacting operation, and withdrawing said second high boiling fraction as an upgraded octane number gasoline product.

12. A method for upgrading the octane rating of a low octane rating gasoline, comprising fractionally distilling said gasoline into a low material which is not easily converted in a subsequent step and a high boiling material more easily converted in said subsequent step, contacting said high boiling material in the vapor phase under Platforming conditions of about 800 to 975 F. and about 300 to 700 p.s.i.g. and in the presence of from 2 to 10 `1:1 mols of free hydrogen per mol Yof said high boiling fraction with a rst platinum containing catalyst as said subsequent' step, withdrawing contacted eluent from this operation, from this first effluent fractionally distilling a low boiling fraction which is susceptible to further octane number improvement; and a high boiling fraction which is not susceptible to further octane number improvement without undue volume loss, combining said low boiling material with said low boiling fraction, contacting this combined material in the Vapor phase under Platforming conditions of about 850 to 1G00 F. and about 250 to 600 p.s.i.g. and in the presence of from 2. to y l0 mols free hydrogen per mol of combined low boiling materials with a second platinum containing catalyst, the temperature of the contactingwith said second catalyst being at a higher temperature than the temperature of contacting with said rst catalyst, the pressure maintained l2 in the second catalytic step being lower than the pressure maintained in the rst catalytic step, `withdrawing contacted ysecond effluent from this second contacting operation, combining eluent of this second vapor phase contacting. operation with eiuent of said rst vapor phase contacting operation, withdrawing said second high boiling fraction as an upgraded octane number gasoline product.

i References Cited in the tile of this patent UNITED STATES PATENTS 2,740,751 Haensel et al Apr. 3, 1956 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No., 2,905,621 September 22, 1959 Robert Du Bauer et al..

It is hereby certified that error appears in theprinted specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

column 7, Alines, 9 and 10, for "3000 no 7000" read 300 to TOO column lO, line 3, for products read product line 55, for "Platformng" read Platforming line 70, after "low" insert boiling Signedandeealed this 14th day of June 1960.,

(SEAL) Attest:

KARL H AXLINE ROBERT C. WATSON Attesting Ofcer Commissioner of Patents 

1. A METHOD FOR UPGRADING THE OCTANE RATING OF LOW OCTANE RATING GASOLINE STOCKS COMPRISING THE STEPS OF CONTACTING IN THE VAPOR PHASE AND UNDER FIRST PLATFORMING CONDITIONS OF ABOUT 800*F TO 975*F. AND ABOUT 300 TO 700 P.S.I.G. A LOW OCTANE VALUE GASOLINE STOCK WITH A FIRST PLATINUM CONTAINING CATALYST, WITHDRAWING EFFLUENT FROM THIS FIRST OPERATION,FRACTIONATING SAID EFFLUENT INTO A LOW BOILING FRACTION WHICH IS SUSCEPTIBLE TO FURTHER OCTANE NUMBER IMPROVEMENT; AND A HIGH OCTANCE NUMBER HIGH BOILING FRACTION WHICH IS NOT SUSCEPTIBLE TO FURTHER OCTANE NUMBER IMPROVEMENT WITHOUT UNDUE VOLUME LOSS, CONTACTING SAID LOW BOILING FRACTION IN THE VAPOR PHASE AND UNDER SECOND PLATFORMING CONDITIONS OF ABOUT 850 TO 1000*F. AND ABOUT 300 TO 600 P.S.I.G WITH A SECOND PLATINUM CONTAINING CATALYST, COMBINING EFFLUENT FROM THIS SECOND OPERATION WITH THE EFFLUENT FROM THE FIRST OPERATION PRIOR TO THE FRACTIONATION STEP AND WITHDRAWING SAID HIGH BOILING FRACTION AS THE UPGRADED OCTANE VALUE PRODUCT OF THE PROCESS. 